Antenna design for mobile phones faces two problems: first, how to obtain a larger bandwidth as much as possible while operating at low-frequency frequency band, and second, how to prevent Specific Absorption Rate (SAR) (which is an indicator for measuring mobile phone electromagnetic radiation intensity) from increasing while operating at high-frequency frequency band. Generally, there exist two commonly-used schemes for mobile phone antenna: Monopole antenna and PIFA antenna. The Monopole antenna has a wide bandwidth but a high SRA, while the PIFA antenna has a narrow bandwidth but a low SRA. In the prior art, it is hard to acquire the optimal performance experience by employing a single Monopole antenna or PIFA antenna in finite space.